Here's what I came up with for a dry dock for my 14. It's made of 2 - 2x6x8 (side rails), 2 - 2x6x10 (front & rear cross pieces), 2 - 2x4x10 (screwed to top edge of cross pieces for stiffening/extra surface for carpet), 2 - 3" Sched 40 pipe (for legs), 2 - 2" Sched 40 pipe + ~2' extra that I had (for diagonal bracing), 4 - 3" x 2" T's (legs to diagonals), 4 - 3" caps (for leg bottoms), 2 - 2" couplings (for added length of diagonals), 4 - 3/8x6 galv hex bolts w/washers & nuts (to fix legs to side rails), and 4 pieces of i/o carpeting which I got for $3 at a carpet shop. I made it for quick assembly/disassembly so I used only 1 bolt thru each leg into side rails and lashed the corners to stiffen it up. Also pulled diagonals into T's under the rig with lashing. Will add a 2x10x8 along center line from front to back to walk on while pulling the boat onto dry dock. Now I'm just hopping over the frame while I pull it up. It's sitting in about 1' of water at the shore side and 2' at the lake side. I made the legs extra long so that I can adjust the frame up in the spring when the water is 12 - 18" higher. I'll put extra holes up each leg at 2 to 3" intervals when I get back to my drill press in the fall. The front and back cross pieces are notched into the side rails so that 1 1/2" of the front and back cross pieces remains above the side rails - this is where the 2x4s are attached.

It looks solid to me, Only thing I can think of is the PVC could end up having problems where its bolted. But if its holding so far then it might be ok. I would consider a treated 4x4 or a Galvanized pipe it the PVC doesn't hold up. But the rest looks sufficient for the small amount of weight it has to carry.

When I lashed the corners the whole structure became quite rigid - no real wave action in the small cove I have it in either. When it comes apart in October the sides and a front and back leg will move as a fairly light weight unit.

The fronts of the hulls actually ride up over the carpet pads very easily, especially with some silicone sprayed on the carpet every now and then.

My lake is about a mile and a half long and a third of a mile wide, with small mountains on either side. We get a lot of squirrely wind here, but the cove is usually quiet - makes for easier launching and docking.